1. Field of the Invention
The present invention generally relates to wireless telecommunication networks. More specifically, the present invention relates to a system and method for providing an open broadcast channel to a group communication, such as Push-to-Talk group communications, in a wireless telecommunication network by increasing the probability that the request to send a group communication will initially receive an open dedicated traffic channel.
2. Description of the Related Art
In a wireless network, the users of wireless communication devices communicate over an air-interface to a central computer. This may be done directly, as in the case of a wireless LAN in an office environment, or it may be done through cellular infrastructure equipment, as in the case of a wireless telephone application. One type of personal communication system is a push-to-talk (PTT) system between mobile wireless communication devices. A PTT communication connection is typically initiated by a single button-push on the wireless device that activates a half-duplex link between the speaker and each member device of the group and once the button is released, the device can receive incoming PTT transmissions once the button is released. In some arrangements, the PTT speaker will have the “floor” where no other group member can speak while the speaker is speaking. Once the speaker releases the PTT button, any other individual member of the group can engage their PTT button and they will have the floor. A specific PTT group of recipient devices for the communicating wireless device is commonly set up by the carrier and the wireless devices themselves do not allow the modification of the group, i.e. to include or drop individuals from the group, or to purposely direct a communication to be received by any fewer members than the entire group.
The typical PTT call involves two users who are rarely located within the same telecommunication sector such that communication and replication of the communication is propagated easily over the existing telecommunication infrastructure. However, a small but very important fraction of push-to-talk calls involve a larger number of call participants, many of whom may also be located within the same sector; public-safety disaster scenarios are one example. In such scenario, the maintenance of the PTT communications within the group all located on the same telecommunication resource is difficult and inefficient. These systems will use “trunks” of the telephone network and standard channel allocation that devote individual circuits for each call participant, thus limiting system scalability.
One problem arises in that a wireless telecommunication device may have a predetermined probability to seize a dedicated communication channel upon request of the user. This delay can minimize the probability of a request collision at the base station. Moreover, in a PTT system, if a large number of receiving wireless devices are in the same sector, there is a high probability that there will be immediate response requests from the group devices, and thus, and increased likelihood of collision. Thus, some internal delay mechanism is desirable to avoid collision, but yet not delay a priority PTT communication. It is thus to such a system and method of reducing latency for the setup of a PTT or direct group communication that the present invention is primarily directed.